"S&P has previously indicated that it believes the U.S. lawsuit was politically motivated, but the language in Tuesday's court filing is its strongest to date.

"The Justice Department 'commenced this action in retaliation for [S&P's] exercise of their free speech rights with respect to the creditworthiness of the United States of America,' lawyers for S&P wrote in court documents filed Tuesday in the U.S. District Court for the Central District of California."

The Justice Department told the Journal that the accusations were "preposterous."

CNN Money reports that the Justice Department rejected the notion the day it announced the lawsuit against S&P:

"At a news conference at the time the suit was filed, Justice Department officials denied there was any connection between S&P's downgrade and the suit being filed. They said the probe into S&P's ratings on subprime mortgages started in 2009. They would not comment at the time whether any other credit agency faced similar legal action."